Abstract

For full-core modeling in the Virtual Environment for Reactor Analysis (VERA), the three-dimensional multigroup eigenvalue neutron transport problem is solved by MPACT. To improve the efficiency of MPACT, advancements have been made in the transport accelerator. Multilevel-in-energy and multilevel-in-space coarse mesh finite difference (CMFD) solvers were developed to improve the efficiency of the CMFD accelerator. In this paper a new multilevel-in-space-and-energy CMFD solver is developed with coarsening in both space and energy on every level. Several different strategies are investigated for coarsening groups in energy. Modified V-cycle and multiple-cycle algorithms are evaluated for solving the multilevel equations. The performance of these solvers is compared for typical full-core reactor physics problems.

摘要

对于反应堆分析虚拟环境 (VERA) 中的全核建模，MPACT 解决了三维多群特征值中子输运问题。为了提高 MPACT 的效率，传输加速器已经取得了进步。开发了多级能量和多级空间粗网格有限差分 (CMFD) 求解器，以提高 CMFD 加速器的效率。在本文中，开发了一种新的多级空间和能量 CMFD 求解器，在每个级别上都对空间和能量进行了粗化。研究了几种不同的策略来粗化能量中的基团。评估修改后的 V 循环和多循环算法以求解多级方程。针对典型的全核反应堆物理问题比较了这些求解器的性能。